ImmunoGen Inc. has won US Food and Drug Administration (FDA) approval for its antibody-drug conjugate (ADC) Elahere (mirvetuximab soravtansine-gynx) for the treatment of platinum-resistant ovarian cancer.
The drug was approved under the FDA’s accelerated pathway and is indicated for adult patients with folate receptor alpha (FRα)-positive ovarian, fallopian tube or primary peritoneal cancers who have received one to three previous lines of systemic therapy. FRα is also known as folate receptor 1 protein (FOLR1).
Elahere targets FRα positive cells through a directed antibody conjugated to a microtubule inhibitor chemo conjugate.
Elahere is the first ADC approved for platinum-resistant disease and ImmunoGen’s first drug approval. It is also the first new drug approval in eight years for advanced ovarian cancer.
During a conference call Tuesday morning, ImmunoGen president and CEO Mark Enyedy said the company will continue to investigate Elahere in platinum-sensitive disease as well.
In the US, ovarian cancer is the leading cause of death from gynecological cancers, and worldwide, it is the eighth most common cancer in women. Approximately 20,000 patients are diagnosed with the cancer each year, and 13,000 patients will die from it. Most patients present with late-stage disease.
Approximately 80 percent of patients with advanced epithelial ovarian cancer will have disease recurrence. Mortality associated with the disease remains high — the five-year relative survival rate for all stages of invasive disease is 49 percent.
The current standard of care for late-stage ovarian cancer is surgery followed by platinum-based chemotherapy and then maintenance therapy. Unfortunately, most patients have, or will develop, resistance to platinum chemo. Given this, standard of care single-agent chemotherapies are associated with low response rates, short durations of response and significant toxicities, said ImmunoGen in a statement. Platinum chemo can also be administered in combination with Roche’s anti-angiogenic therapy Avastin (bevacizumab) in patients with advanced disease.
Of significance, Elahere has a relatively broad label approval as it can be used irrespective of prior treatment with Avastin. ImmunoGen said this allows the treatment to be available to about 5,200 patients in the US.
In a news release from ImmunoGen, Anna Berkenblit, MD, senior vice president and chief medical officer of ImmunoGen, said Elahere’s approval was a “tremendous advance in the ovarian cancer treatment paradigm,” for which no treatment has been approved since 2014.
Other ADCs include AstraZeneca’s Enhertu, Seagen’s Padcev and Gilead’s Trodelvy.
Elahere comes with a black box warning of possible ocular toxicities such as dry eye, uveitis and visual impairments.
Elahere’s approval was based on results from the pivotal SORAYA trial that involved 106 patients with platinum-resistant ovarian cancers whose tumors had high expression levels of FRα. The single-arm study evaluated the objective response rate (ORR) with respect to tumor shrinkage and duration of response after Elahere treatment. The ORR was found to be 31.7 percent, including five complete responders, and lasting for a median duration of 6.9 months. All participants had previously been treated with Avastin.
MIRASOL, a confirmatory trial to convert Elahere’s accelerated approval to full approval, is now fully enrolled, ImmunoGen reported. Initial readouts are expected early next year.
Additionally, ImmunoGen is also looking to receive clearance for the use of Elahere in combination with Avastin in the platinum-resistant setting. This would add an additional 1,800 FRα patients to the “market opportunity,” Enyedy said in a conference call.
In the call, Enyedy also revealed Elahere’s list price for a 20 mg dose to be $6,220. Patients are typically administered three to four vials in a treatment cycle, bringing the total cost of the therapy to be approximately between $18,500 and $25,000.
Enyedy added that the company is ready to launch Elahere “within days.”
Complementing the approval, the FDA also green lit a Roche diagnostic to help determine patient eligibility for Elahere based on FRɑ expression levels. The Ventana FOLR1 RxDx Assay is the first immunohistochemistry (IHC) companion diagnostic test designed to identify epithelial ovarian cancer patients that would benefit from Elahere.